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Cat food calculator
Put your cat’s weight, activity factor, calories per cup and meals per day in: a 10 lb indoor cat at activity factor 1.2 needs 261.1 kcal a day — 0.75 cups at 350 kcal a cup, 0.37 cups a meal.
★ HEALTH · PETS · CATS
Cat Food Calculator: 0.75 Cups a Day for a 10 lb Cat
On the defaults — a 10 lb indoor cat at activity factor 1.2 — the cat needs 261.1 kcal a day, 0.75 cups at 350 kcal a cup, 0.37 cups at each of 2 meals. This is the cat food tool: turn pounds into kilograms, raise to the three-quarter power for resting energy, multiply by activity, and divide by the food’s calories — a bowl filled by eye feeds a different cat every day.
What does 0.75 cups a day, 0.37 cups a meal mean?
It means a 10 lb cat weighs 4.54 kg, and the resting-energy power law gives 217.6 kcal at rest — 70 times the weight in kilograms raised to 0.75 — which an indoor adult’s activity factor of 1.2 lifts to 261.1 kcal a day. At 350 kcal a cup that is 0.75 cups a day, split over 2 meals as 0.37 cups each. The weight sets the resting energy, the activity factor scales it, and the food’s calories per cup turn energy into the scoop — three steps, in that order, and the only judgement is the activity factor.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Weight in kg | pounds ÷ 2.20462 | 4.54 kg — 10 ÷ 2.20462. |
| Resting energy (RER) | 70 × kg^0.75 | 217.6 kcal — 70 × 4.54^0.75. |
| Daily energy | RER × activity factor | 261.1 kcal — 217.6 × 1.2. |
| Cups a day | daily ÷ kcal per cup | 0.75 cups — 261.1 ÷ 350. |
| Cups a meal | cups a day ÷ meals | 0.37 cups — 0.746 ÷ 2. |
Three things to check before you trust the number
First, check the activity factor honestly: 1.2 is an indoor adult, 1.4 is an active adult, and a kitten or a nursing queen needs far more — the factor, not the weight, is usually where the bowl goes wrong. Second, check the calories per cup off the bag, not off memory: foods range widely, and a cup of one food can carry half again the calories of another. Third, weigh the cat, don’t guess it: a pound either way moves the daily energy by roughly 25 kcal, and a cat fed for a guessed weight drifts fat or thin by ounces a month, which is how a small error becomes a vet visit.
Worked example
10 lb, activity factor 1.2, 350 kcal a cup, 2 meals a day. Weight: 10 ÷ 2.20462 = 4.54 kg. Resting energy: 70 × 4.54^0.75 = 217.6 kcal. Daily: 217.6 × 1.2 = 261.1 kcal. Cups: 261.1 ÷ 350 = 0.75 cups a day. Per meal: 0.746 ÷ 2 = 0.37 cups. In practice that means a level three-quarter cup a day, split as a level third of a cup at each of two meals — a measuring cup, not a mug, because a mug’s idea of a cup is nobody’s.
Every branch, checked
With a 15 lb cat instead of 10 lb, the resting energy rises to 294.9 kcal, the daily to 353.9 kcal, and the food to 1.01 cups a day, 0.51 cups a meal. With an activity factor of 1.4 instead of 1.2, the daily rises to 304.6 kcal, 0.87 cups a day, 0.44 cups a meal. With a food at 300 kcal a cup instead of 350, the same 261.1 kcal needs 0.87 cups a day, 0.44 cups a meal. With 3 meals instead of 2, the day stays 0.75 cups but each meal falls to 0.25 cups.
The reverses, worked backwards
The weight behind 0.75 cups is 10 lb: at 8 lb the need is 0.63 cups a day (3.63 kg, RER 184 kcal, 220.8 kcal a day, activity factor 1.2, 350 kcal a cup, 0.32 cups a meal, 2 meals a day); at 12 lb it is 0.86 cups a day (5.44 kg, RER 249.5 kcal, 299.3 kcal a day, activity factor 1.2, 350 kcal a cup, 0.43 cups a meal, 2 meals a day). The activity factor behind 0.75 cups is 1.2: at 1.0 the need is 0.62 cups a day (4.54 kg, RER 217.6 kcal, 217.6 kcal a day, activity factor 1, 350 kcal a cup, 0.31 cups a meal, 2 meals a day); at 1.4 it is 0.87 cups a day (4.54 kg, RER 217.6 kcal, 304.6 kcal a day, activity factor 1.4, 350 kcal a cup, 0.44 cups a meal, 2 meals a day). The calories per cup behind 0.75 cups are 350 kcal: at 300 kcal the need is 0.87 cups a day (4.54 kg, RER 217.6 kcal, 261.1 kcal a day, activity factor 1.2, 300 kcal a cup, 0.44 cups a meal, 2 meals a day); at 400 kcal it is 0.65 cups a day (4.54 kg, RER 217.6 kcal, 261.1 kcal a day, activity factor 1.2, 400 kcal a cup, 0.33 cups a meal, 2 meals a day).
What the defaults assume
The defaults assume a 10 lb indoor adult cat at activity factor 1.2, eating a 350 kcal-a-cup food over 2 meals. They do not assume kittens, nursing queens, weight-loss plans, or prescription diets — a kitten’s factor runs far higher, a weight-loss plan wants a vet’s target, and a prescription food’s calories come off its own bag, not this calculator’s default.
Who uses this
- A new cat owner setting the bowl: the 0.75-cup day settles the scoop before the first bag is opened.
- A multi-cat household splitting food: the per-meal figure off the calculator is the line per bowl, not a shared guess.
- A vet nurse checking an owner’s maths: the weight, RER and activity figures are the lines to check, not the bowl.
- A foster carer weighing a rescue: the same maths on each weigh-in tracks the food as the cat gains.
Accuracy & limitations
The arithmetic is exact for the inputs entered; the judgement is the activity factor and the weight. Real cats vary with age, breed, neutering and health, and the RER power law is a planning formula, not a metabolic measurement — the scale, the bag’s calorie figure and the cat’s own body condition override any planning number. Treat 0.75 cups as the planning day for a 10 lb indoor cat on a 350 kcal-a-cup food, and check with a vet if the cat is gaining, losing, ill, or on a special diet.
Cite this calculator
Bright Side Kit, “Cat Food Calculator: 0.75 Cups a Day for a 10 lb Cat”, https://brightoolbox.com/cat-food-calculator/, accessed 3 November 2026. Students and researchers: cite the calculator name, the page URL and the date you used it, and quote the defaults (10 lb cat, activity factor 1.2, 350 kcal a cup, 2 meals a day) so the result can be checked.
Frequently asked questions
How much should I feed a 10 lb cat?
0.75 cups a day on the defaults: 261.1 kcal a day at activity factor 1.2, split as 0.37 cups at each of 2 meals, on a 350 kcal-a-cup food.
What is RER, and why the 0.75 power?
Resting energy requirement: the energy a resting animal burns, which scales with weight to the three-quarter power, not in proportion — a cat twice as heavy needs about 1.68 times the resting energy, not twice. The formula is 70 × kg^0.75.
What activity factor should I use?
1.2 for an indoor adult, 1.4 for an active adult, and higher for kittens or nursing queens. The factor is the biggest judgement in the calculator — an honest factor matters more than a precise weight.
How is this different from the dog food calculator?
It is built for cats: the feline RER power law and cat activity factors, with cat feeding guidance. The dog page is built for dogs, with its own factors and guidance — use the page for the species you feed.
What if my cat is overweight?
Then the goal is a vet’s target weight and a planned reduction, not this calculator’s maintenance figure at the current weight. Ask the vet for the target, then run the calculator at the target weight.
Do kittens use the same maths?
The power law is the same, but the activity factor is far higher — kittens grow fast and eat for growth as well as maintenance. Use a kitten factor from your vet, not the 1.2 indoor-adult default.